Photoacoustic imaging technology is being studied, where an object is irradiated by light, and image data of the object is acquired using acoustic waves (photoacoustic waves) emitted by the photoacoustic effect, due to energy of the light being absorbed. There is a technique in photoacoustic imaging where image data sets of an object acquired by multiple irradiations of light are composited.
However, there is a possibility that the relative positional relationship between the object and the photoacoustic wave reception unit may change from one light irradiation to another. This causes positional displacement due to the change in the image data corresponding to each light irradiation. The result is that image data sets of the object that include positional displacement are composited with each other, and the quality of the composited image data sets of the object is lower. There is known a technique that addresses this problem by comparing the image data sets with each other, thereby estimating and correcting the positional displacement of the image data sets.
PTL 1 discloses estimating positional displacement amount by comparing the image data sets of the object with each other, and compositing the image data sets of the object after the positional displacement has been corrected. However, there is demand for further improvement in estimation precision regarding the positional displacement estimation method according to PTL 1.